In a traditional radio network, a sending node is in a one-to-one correspondence with a receiving node, that is, one sending node sends data to only one receiving node. Further, to-be-sent data is stored in a buffer inside a sending node, for example, in a buffer of a Packet Data Convergence Protocol (PDCP) entity and in a buffer of a Radio Link Control (RLC) entity, where the RLC entity is associated with the PDCP entity.
With the development of radio network technologies, a sending node and receiving nodes may be in a one-to-many correspondence, that is, a sending node may send data to two or more receiving nodes. In this case, the sending node generally includes two or more RLC entities that are respectively corresponding to the two or more receiving nodes, and the two or more RLC entities are all associated with a PDCP entity.
For example, in a case in which a sending node sends data to a receiving node A and a receiving node B, the sending node includes RLC entities A and B that are respectively corresponding to the receiving nodes A and B; and the RLC entities A and B are both associated with a PDCP entity.
Generally, before sending data, the sending node needs to report a buffer status to the receiving node, so as to request the receiving node to allocate a sending resource, where the buffer status indicates a size of to-be-sent data. In the prior art, in a case in which a sending node and receiving nodes are in a one-to-many correspondence, because all RLC entities are associated with a PDCP entity, Buffer Status Reports (BSR) for all receiving nodes are triggered when there is to-be-sent data in a buffer of the PDCP entity; and as a result, all the receiving nodes allocate sending resources for this part of data, thereby causing a waste of resources.
For example, in a case in which a sending node sends data to receiving nodes A and B, if there is a to-be-sent data in a PDCP entity, the sending node triggers BSRs A and B. The BSR A is used to report a buffer status to the receiving node A based on a size of to-be-sent data in a buffer of the PDCP entity and in a buffer of an RLC entity A. The BSR B is used to report a buffer status to the receiving node B based on a size of to-be-sent data in the buffer of the PDCP entity and in a buffer of an RLC entity B.
Because the BSRs A and B both calculate the size of the to-be-sent data in the buffer of the PDCP entity, the receiving nodes A and B both allocate a sending resource to the to-be-sent data in the buffer of the PDCP entity, which obviously causes a waste.